MICROPOROUS FILM FOR POWER STORAGE DEVICE SEPARATOR AND POWER STORAGE DEVICE SEPARATOR MAKING USE OF THE SAME

摘要

[PROBLEMS] To provide a microporous film for power storage device separator that when used in a power storage device, can increase the energy density and output density thereof, and that in the processing to power storage device, excels in handling easiness, and provide a power storage device separator and power storage device making use of the same. [MEANS FOR SOLVING PROBLEMS] There is provided a microporous film for power storage device separator, characterized by exhibiting a porosity of 70% or higher, a lengthwise strength of 40 MPa or greater and an average pore diameter of 40 to 400 nm, and having nonnuclear pores, and being biaxially oriented.